Hoogenraadia africana Gauthier-Lièvre & Thomas, 1958
Diagnosis: Test ovoid-globular, more or less elongated; at its small end occupied by the pseudostome which is surmounted by a visor that covers it while being rolled up on itself. The pseudostome, which is terminal and circular or nearly so, is concealed by this visor which is only the extension, on one side, of the sides of the theca. This curved visor, located at a distance above the pseudostome, and indented laterally, thus provides a covered walkway in the manner of an awning. The test seen in profile, according to whether it is examined in a right or left position, takes the form of a printing press or the number 6. From the front, the opening of the pseudostome is visible only in order to plunging and provided that the visor-belly space is open enough. This visor, extension of the flanks, is strongly fixed on both sides, up to half the diameter of the theca. The test is chitinoid, brownish yellow, covered with well-fixed platelets, larger on the body, never overflowing as it is observed at Centropyxis and Cyclopyxis. On the visor, the edge of the latter, the pseudostome’s turn, are arranged tidy plates.
Dimensions: Length 95-115 μm; diameter 47-60 μm; aperture 29-35 μm; height of the edge of the pseudostome at the top of the visor in frontal view 20-32 um.
Ecology: Africa: Middle Congo: According to our observations, this species seems very widespread in the North-East of the Middle Congo in the marshes, ponds and backwaters established on Kalahari sands with acidic waters or heavily loaded with humic substances.
Remarks: Gauthier-Lièvre and Thomas (1958) wrote: “The animal could not be observed alive but it is likely that Hoogenraadia africana is placed near the genera Centropyxis and Plagiopyxis and belongs to the same family. We did not want to associate it with the genus Plagiopyxis, because contrary to what one observes in this one, the ventral edge does not participate in the dissimulation of the opening of the pseudostome which, according to the inclination of the visor, is always quite easily visible.”